Adjustable length windshield wiper arms



Nov. 7, 1950 T. J. SMULSKI ADJUSTABLE LENGTH WINDSHIELD WIPER ARMS 2Sheets-Sheet 1 Original Filed Feb. 11, 1944 II .//////////n 1 INVENTOR.

THEODORE J. SMULSKI ATTORNEY Nov. 7, 1950 T. J. SMULSKI ADJUSTABLELENGTH WINDSHIELD WIPER ARMS 2 Sheets-Sheet 2 Original Filed Feb. 11,1944 THEQDOIEE J. SMULSK/ HY n m d5 Rm do. n d 3 9 G m I l I 2 2 2% SwPatented Nov. 7, 1950 ADJUSTABLE LENGTH WINDSHIELD WIPER ARMS TheodoreJ. Smulski, Gary, Ind., assignor to Productive Inventions, Inc., anIndiana corporation Original application February 11, 1944, Serial No.

1946, Serial No. 659,981

Claims. (CI. -250) This invention relates to adjustable length wiperarms for windshield wipers. In wiper arms of. this kind supporting andsupported arm sections are provided, the supported section beingadjustable lengthwise of the supporting section, and the wiper bladebeing carried by the outer end of the supported section. The means forrelatively fixing the sections in different positions of adjustment havebeen of two classes.

In wiper arms of the first class the supported section is formed with aseries of notches and the supporting section with a non-releasablespring detent for engaging the notches. This arrangement has theadvantage that there is no tendency of the arm sections to creep, underthe influence of centrifugal force and the impact of repeatedvibrational shocks, and thereby to extend the arm to an effective totallength greater than that for which it was intended to be set. It has thedisadvantage, however, that the detent spring must be made fairly stiffand strong in order to prevent slipping. There is no relaxation of thepressure of the detent for adjustment purposes, and hence the operatoris required to overcome-the full normal holding force of the detent inorder to effect a desired adjustment.

This is an especially disadvantageous mode of operation in aircraftwipers. The high velocity of aircraft increases the rate of deposit ofpre-.

cipitation upon the windshield and makes a relatively high speed ofwiper operation desirable. The high relative air speed makes itdesirable to bias the wiper blade against the aircraft windshield withheavy pressure as compared with the biasing pressure employed in surfacevehicle installations. Both these considerations dictate the use ofrelatively powerful wiper motors in aircraft, so that the forces towhich aircraft wiper arms are subjected are increased all round ascompared with surface vehicle wiper arms. The

normal holding force employed in aircraft installations for securing thewiper arm sections in adjusted relation must, therefore, be verysubstantial.

Other factors which weigh against wiper arms of this class are that theoperator is-likely to be in an awkward position for exerting anysubstan-' I Divided and this application April 5,

tive adjustment, the clamp being operable to nonclamping condition forthe purpose of facilitating adjustment, and to a clamping condition forthe purpose of opposing relative movement of the parts during operation.This arrangement has the advantage that the desired ease of adjustmentmay be realized.

The employment of frictional clamping, however, is not generallyapproved by aircraft engineers. It is feared that because of therelatively great forces involved in aircraft wiper operation, andbecause of the shock and vibration to which aircraft is subject, thatthe friction clamp may relax its grip momentarily from time to timeunder the influence of shock, so that there may be a slow andprogressive change in the total eifective length of the arm in use.

Tests have been conducted by me with wiper arm structures designed topermit creeping for ascertaining what tendencies toward creeping arepresent and have shownv that in some forms of wipers the adjustablesection tends to creep outward under the influence of centrifugal force,while in other forms of wipers the adjustable section tends to creepinward in response to various factors such as the lengthwise componentof the pressure exerted by the biasing spring, and side forces havinglongitudinal components which come into play at each reversal ofdirection of the wiper arm.

The creeping does not depend upon the occurrence of shock and vibration,but it may be promoted by the presence of a very slight lateral playbetween the relatively adjustable wiper arm sections. As the adjustablesection is caused to shift slightly from side to side relative to thesupporting section, and is urged inward or outward, it works its wayalong very gradually by zigzag steps having a relatively large lateralcomponent and a relatively slight longitudinal component, a forcemultiplying principle coming into play analogous to that of the inclinedplane.

The present application is a division of my copending'application,Serial No. 521,903, filed February 11, 1944, now Patent No. 2,507,229,May 9, 1950.

The primary object of the present invention is to provide a structurewhich combines easy adjustment with assured retention of adjustedlength. 7

In accordance with one practical and advantageous illustrativeembodiment of the invention, this object is realized by providingnotches in the supported section, a detent cooperative therewith, andmeans normally pressing the detent forcibly 3 into engagement with thenotches but operable at thewill of the operator to reduce or remove thepressure uponthe'detent when adjustment required. I 1' x 4 I L Inaccordance with another practical and adformed with faces substantiallyat right angles to the lengthwise dimension of the arm. sothat thedetent becomes in eflect a positive locking member.

It is an important feature of the invention. equally applicable toeither of the illustrative forms referred to, that the means forpressing the detent and the supported wiper arm section togetherincludes a yieldable resilient element, the means for pressing thedetent forcibly into engagement with the adjustable supported sectionbeing operable to looking or detaining position even if'the detainingportion of the detent be located between successive notches.

The feature of providing a yieldable resilient element in the detentclamping mechanism is important, not only because it saves the time ofthe workman, but more particularly because it avoids breakage anddisabling distortion of parts.

Other objects and advantages will hereinafter appear.

In the drawing forming part of this specification,

Figure 1 is a fragmentary view'in rear elevavation, partly broken away,of a windshield wiper arm embodying features of the present invention;

Figure 2 is a fragmentary view in longitudinal section of the structureillustrated in Figure l, the section being upon the line 2-2 of Figure 1looking in the direction of the arrows;

Figure 3 is a sectional view taken upon the line 3-3 of Figure 2 lookingin the direction of the arrows;

, power. motor.

ating shaft 8. The actuating shaft may be oscillated manually or throu hthe operation of a A second wiperarm section] comprising a channeledmember 5 is pivotally mounted upon section 2 through the medium of across pin or rivet 8 which, is passed through the section ,2'and'through end portions of the channel walls of the member 5. Thewiper section 4 is yieldingly biased toward the windshield by means ofan adjustable spring unit I and associated parts. The spring unitcomprises a series of leaves 8 which are bound together at their outerends in fixed relation to one another. being held asa portion of thespring 9 and the outer ends of the leaves 8 inflxed relation to oneanother Figure 4 is a sectional view taken upon the A line 4-4 of Figure2 looking in the direction of the arrows;

Figure 5 is a fragmentary sectional view taken upon the line 5-5 ofFigure 1 looking in the direction of the arrows;

Figure 6 is a detail perspective view of a supporting and guiding plateillustrated in Figures 1, 2, and 5; v

Figure 7 is a fragmentary view in rear elevation of another windshieldwiper arm embodying features of the invention;

Figure 8 is a longitudinal sectional view taken substantially on line8-8 of Figure 7;

Figure 9 is a fragmentary view in transverse section of the structureillustrated in Figure 8, the section being taken upon the line 99 ofFigure 8, looking in the direction of the arrows;

Figure 10 is a fragmentary sectional view taken upon the line Ill-40 ofFigure 8 looking in the direction of the arrows; and

Figure 11 is a perspective -view of a modified form of a supporting andguiding plate.

In Figures 1 to 6, inclusive, disclosure is made of a windshield wiperarm and parts thereof, which is easily adjustable as to length, but inwhich retention of adjusted length may be assured. The illustrative armis desirably ofthe kind illustratively disclosed in Letters Patent ofthe United States No. 2,326,402, granted to me on August 10, 1943, forWindshield Wiper Arms.

The arm I comprises an inner arm section 2 which is rigidly and firmlysecured to an actuand to the holding member. The inner end of the springassembly formed by the leaves 8 bears against a roller [2 which isrotatively mounted on a cross pin 13 which forms part of the wiper armsection 2.

A screw I4 having its head formed with a screwdriver slot has its shankand body passed through an opening in the front wall of channel member 5and through a spacing collar [5, the body of the screw being threadedthrough an ear I6 formed on the inner end of the member I0. Turning ofthe screw l4 to draw the ear l6 toward the front wall or base of thechannel member 5 increases the bias with which the section 4 is urgedrearwardly toward the windshield.

The structure just described difiers from the disclosure of Patent No.2,326,402 in one significant feature. The member ID has no rocking earsfor bearing against the front or base wall of the channel member 5, butis instead supported and spaced from the front or base wall by the sidewalls of the channel member 5. Thus the side wall of member 5 may bemade to define a channel adjacent the front wall thereof which isunobstructed and of uniform width from the outer end of the member 5allthe way inward to the screw and the collar l5. This provides auniform, clear channel for a lengthwise adjustable wiper arm sectionwhich will be more particularly referred to and described presently.This manner of support for the member I0 is clearly illustrated in'Figure 3 in which the channel side walls of .member 5 are shown ascomprising forward parallel portions 51:, rearwardly divergent, shoulderformin portions 5g, and rear parallel portions 52. The member I 0bottoms against, and rocks upon the shoulder.

.section 4, being adjustable lengthwise thereof.

The arm section I! is slidingl supported and guided between the frontwall of channel member 5 and a notched guide plate l8 which, to-' getherwith the channeled member 5 forms a guiding throat for the adjustablesection ll.

The plate I8 is disposed at the rear of section l1 and rests in cutoutsformed in the rear margins of the side walls of channel member 5.Fingers I! which extend rearward from the side walls of channel member 5are received in the notches 28 of the guiding and retaining plate 1-8and in notches 2| formed in a. broadened portion of the spring 9. Thefingers l9 are folded inwardly against the rear face of the spring 9 toretain the channeled member 5, the plate Land the spring 9 in fixedrelation to one another. The plate 18 is normally slightly bowed andyieldable and does not bear with substantial pressure against the wiperarm section II, but provides a substantially free passage therefor.Plate I8 serves not only as a guiding and retaining member, but also asa stop fOl' cooperating with a shoulder 22 formed near the inner end ofarm section II, for positively preventing complete separation of thesection I! from the section 4.

One extremity of the plate I8 is provided with a wedge-shaped nose ordetent 26 which is adapted to be lodged selectively in any one of amultiplicity of notches 21 formed at desired intervals in the rear faceof wiper section ll.

The detent 26 is normally pressed forcibly forward against the member Hby a wedging semaphore lever 28 whose construction and support desirablycorrespond to the construction and support of the corresponding partsdisclosed and claimed in my Patent No. 2350,134, dated May 30, 1944, forExtensible Wiper Arms.

The construction and mounting of the lever 28 are briefly as follows.The outer end of the spring 9 is formed with a bowed or arched portion29 and has a circular opening 39 formed in the keystone portion of thearch. The sema pbore le er 28 includes a rearwardly extending tailportion 3| which passes rearwardly through the opening 3|). The lever 28includes a wedging body ortion 32 which cooperates with a cam portion 33of the spring 9 and .with the detent 2G. The lever also includes anoperating finger iece 34 which extends in a fore and aft plane substntially at right angles to the plane of the portion 32.

When t e s map ore lever 28 is operated to the posit on illu trated inFigure 1, it extends in ali nment with the wi er arm and is inconspicuoulv lo ated as viewed from the driver's seat. It is retained in this poition by a notch 3'5 form d in t e extremity of the s rin 9, and it iscaused b the s ring to hear forcibly a ainst the late I8 for stron lvresisting a rearward displ c ment 01' t e plate far enough to permit thenose or detent 2G to clear a notch of t e membar I! in which it is rceived. This is the normal o erating condition of the arts, and with thedetent or nose thus clamped in a notch of the member H. the maintenanceof the desired l ngthwise adjustment of the arm is assured. I

The eff ct of shock or v bration will be rather to assure the centeringof the nose in the notch rather than the withdrawal of the nose from thenotch.

When it is desired to ad ust t e effective len th of the arm, thesemaphore lever 28 is op rated from the full line position illustratedin Fi ure l to the dotted line position illustrated in that figure. Inthe latter position the lever 28 extends conspicuou ly to one side ofthe wiper arm as viewed from the driver's seat, serving as a conspicuouswarning that the lever is in the unlocking position and that thelengthwise adjustment of the wiper arm is not fixed. In this unlockingposition, the lever 28 is moved out from under the cam portion 33ofspring 9 and extends in the space between opposite walls of the springarch. It is retained in this position by engagement with the arch walls,but exerts no important pressure against-the detent.

The outer extremity of the plate carrying the detent 26 springs slightlyoutward when the pressure of the lever 28 against it is relieved. Itcan, however, be freely cammed aside when the arm section I! is pulledor thrust to adjust the effective length of the arm, so that the detentoffers no substantial resistance to such lengthwise adjustment.

When the desired adjustment has been eflected or substantially effected,the lever 28 is returned to the full line position illustrated in Figure1 to lock the parts in the selected adjusted relationship. While thelever 28 can be more readily returned to the locking position if thenose 26 directly enters a notch 21, the operation of the lever to thelocking position is not prevent d by engagement of the nose with araised surface between two adjacent notches, nor is any damage done byforcing the lever to locking position. The spring 9, though stiff, isresilient and sufficientls yieldable to permit such operation withoutinjury to the parts. When the lever is so operated the lever and detentserve to clamp the parts frictionallv in place with a very firmpressure, but still there may be a relative creep. Such creeping,however. will in no event extend beyond the point at which the detentnose first ncounters a notch. In other words. the creeping will belimited to a fraction of the distance etween adiacent notches and theretention of t e parts in substantially the relative ositions in whichthey were adjusted will. therefore, be assured.

In Fi ures 7 to 11. inclusive. another form. oi construct on embodyingthe invention is illustrated. Since the parts are in the main duplicatesof the parts illustrated in Figures 1 to '7, inclusive, correspondingref r nce charact rs ha e been applied to corresponding parts with thesubscript a added in each instance. and the deta led description ofthese arts will not be rep ated. The ensuin descr t on will be confinedto those arts in Figures 8 to ll which are snecifinallv diff rent fromthe corresponding par s of Figures 1 to '7. v

he adiustable wiper arm sect on "a is formed with sou-are notches 4i anda holding member 42 is prov d d with a squ re nos 43 for cooperationwith the snuare otches. The inner end of th ho din member 4.2 is rovidedwith pro ect ons 44 and 45 which rest in notches formed in the rear marins of the side wa ls of channel member 5a. The pro ections 44 and 45are separat d bv a no ch 45 through which fingers l9a of the side wallmembers extend. The fingers also extend thro gh notch s 2m of the spring9a and are folded down against the rear face of the spring 9a to holdthe chann l member 5a, the

spring Pa and the inner end of the holding member 42 fixedly in place.

Because the souare notches and the souare nose form an absolutelypositive locking means, so that the notches have no capacity to cam thenose to one side, the holding member is made of s ring material whichhas the tendency normally to spring rearward and carry the nose 43 outof an associated notch 41!. The term square as h rein used includes aconfiguration having four equal angles which may be a square orrectangle. The semaphore lever 28a comprises the same parts as the lever28 and is mounted in the same manner in an arched por- 1 bodily movementin a forward direction. reason of the engagement of the ears in the tion29a of spring so thatthe lever 281s mounted in the arched portion 28 ofspring 9. v When the parts are in the positions illustrated in Figures 8and 9, the lever 28a maintains the nose 43 of the holding member 42 in anotch 4| with suflicient force to absolutely preclude all possibility ofaccidental dislodgment. When the lever 28a is operated to unlockingposition, the holding member 42 springs rearward, causing the nose 43 toclear the rear face of the member 11a. The member l'la may then befreely adjusted and-the lever 28a restored to locking position.

As in the case of the structure illustrated in Figures 1 to 7, it is notnecessary that the nose 43 engage in a notch 4| in order for the lever28a to be fully operated to locking position. As in the former case, ifthe nose 43 comes to bear upon a raised surface in a space betweennotches, there will be no relative creeping of the parts beyond thepoint where an adjacent notch has been shifted into registration withthe nose.

As soon as this condition of registration occurs, the nose 43 will beforced to enter the notch and all further disturbance of the lengthwiseadjustment of the parts will be positively precluded.

The construction of the channeled member 5a and the mounting of thespring unit Illa upon the channel member are specifically different fromthe corresponding features of Figures 1 to 7. The channeled member 5a isformed with straight side walls 5q, and the unit Illa is supportedrearwardly of the adjustment path of supported section Ila by the rearcover spring 9a. The rear cover spring 9a is formed with laterallyprojecting ears 9x which bear in notches 51' formed in the rear faces ofthe side walls Sq. The ears and notches are located closely adjacent tothe point of connection of the rear cover spring to the spring unitIlla. The ears bear against rearwardly facing surfaces of the side walls5q and restrain the spring unit against By notches, movement of thespring unit Illa lengthwise of the arm is substantially precluded.Adjusting operation of the spring unit I lie into obstructing relationto the adjustment path of 1 the supported section Ila is precluded bythe stop collar I50.

I have described what I believe to be the best embodiments of myinvention. I do not wish, however, to be confined to the embodimentsshown, but what I desire to cover by Letters Patent is set forth in theappended claims.

I claim:

1. In a windshield wiper, in combination, a supporting section, asupported section carried thereby with capacity for longitudinal adiu"ment relative thereto, a spring unit carried by r the supporting sectionfor engagement with a still further wiper arm section upon which thesupporting section is carried, to bias the sup- I porting and supportedsections toward a windshield, means carried by the supporting sectionfor adjusting the spring unit to alter the spring bias, said supportingsection including a front body member and side walls disposed rearwardlythereof, the side walls including forward portions adjacent the frontbody member for defining with the front member a continuous channel forthe reception of the supported wiper arm section, said side wallsengaging and sustaining the spring unit rearwardly of said channel andpreventing operation of the spring unit into a channel obstructingposition, and rear stantially contained.

2. A windshield wiper structure adapted for se in a wiper arm whichcomprises a first inner section adapted to be amxed forwardly of awindshield to an operating shaft and including an abutment, a secondnext outer channeled section pivotally mounted on the first section formovement about an axis transverse to the shaft axis, and a third sectionmounted in the channeled second section with capacity for adjustmentlongitudinally thereof, said windshield wiper structure comprising, incombination, the channeled second section referred to, said secondsection including a front body member and rearwardly projecting sidewalls, a spring unit carried by said channeled section, said spring unitcomprising -a forward leg and a rear leg united to one another throughtheir outer ends the second section is operatively installed to forcethe free inner end of the forward leg of the spring unit progressivelytoward said front body member, thereby to increase the separation of theforward and rear legs against increasing spring resistance as theforward le is adjusted forward toward the front body member, the sidewalls of said channeled second section including forward parallelportions adjacent the front body member for defining with the front bodymember a continuous guide channel for the revception of the third wiperarm section, intermediate shoulder forming portions engaging the forwardleg of the spring unit for rockingly sustaining said leg and preventingits operation into a channel obstructing position, and rear portionsmore widely spaced than the forward portions, between which the springunit is substantially contained.

3. In a windshield wiper, in combination, a supporting section, asupported section carried thereby with capacity for longitudinaladjustment relative thereto, an adjustable spring unit carried by thesupporting section for biasing the supporting and supported sectionstoward a windshield, means for adjusting the spring unit to alter thespring bias, said supporting section including a front body member andside walls disposed rearwardly thereof, the forward portions of the sidewalls adjacent the front body member defining with the front body membera continuous channel for the reception of the supported wiper armsection, said side walls extending rearwardly substantially beyond theadjustment path of the supported section, and a rear cover springaflixed to said side walls and to said spring unit, said cover springincluding portions adjacent the point of connection with the spring unitwhich bear against the side walls, operatively to support the springunit in rear of the adjustment path of the supported section.

4. In a windshield wiper, in combination, a supporting section, asupported section carried thereby with capacity for longitudinaladjustment relative thereto, an adjustable spring unit carried by thesupporting section for biasing the supporting and supported sectionstoward a windshield, means for adjusting the spring unit to alter thesprin bias, said supporting section including a front body member andside walls disposed rearwardly thereof, the forward portions of the sidewalls adjacent the front body member defining with the front body membera continuous channel for the reception of the supported wiper armsection, said side walls extending rearwardly substantially beyond theadjustment path of the supported section, and a rear cover springaflixed to said side walls and to said spring unit, said cover springincluding projections adjacent its point of connection with the and sidewalls, said channel also having an inner extremity pivotally connectedto the inner section, an extensible outer section seated in the channeland having means at its end for attaching a wiper unit thereto,adjustable actuating means provided with an end for engaging the sidewalls of the channel at a point intermediate the extremities of saidchannel whereby to provide clearance for the movement of said extensibleouter section, and a spring device operatively connected to the innersection having a part anchored against movement with respect to thechannel and a part actable on said actuating means to cause its said endto engage the side walls of the channel.

THEODORE J. SMULSIQ.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,245,244 Zaiger June 10, 19412,826,402 Smulski Aug. 10, 1943 2,332,660 Mussen Oct. 26, 1943

